The TD100 Data Manager is a DOS PC designed to mount on top of TDS500,TDS600, and TDS800 oscilloscopes. It came preconfigured with S34TDS1 data manager software and included a 40MByte hard disk and a 1.44 MByte 3.5" floppy drive. It was produced by RadiSys Corp. under the designation 131816.
Note that the TD100 in the catalog picture is labeled "Tekmate" like the 2402, but the actual product seems is labeled "Data Manager".
TD100 on top of TDS540 scope from 1993 catalog.